N=4x2+4x+1
= (2x+1)2
do (2x+1)2 \(\ge0\forall x\)
MinN=0 khi 2x+1=0
=>2x=-1
=>x=\(\dfrac{-1}{2}\)
N =4x2+4x+1
=(2x+1)2
do (2x+1)2\(\ge\) 0 \(\forall\) x
Min N =0 khi 2x+1=0
=>2x=-1
=>x=-\(\dfrac{1}{2}\)
Tìm max hoặc min của A= -2x^2-8x+1
B=3x^2+3x-1
C=7x-2x^2+3
D=-4xy+4x-y^2-5x^2+3
Tìm x, biết
a) 4(x+2) - 7(2x-1) + 9(3x-4) = 30
b)2(5x-8) - 3(4x-5) = 4(3x-4) + 11
c) 4x2 + 3(2x2+1) = 2x(5x-7)
d) x(x2-7) = 2x(\(\dfrac{1}{2}\)x2+6) + 8
1.Làm tính nhân.
a) 3x2(4x3-2x+\(\dfrac{1}{3}\))
b) (4x2+8xy-3xy2).(\(\dfrac{-3}{4}\)x2y)
c) 4x3(2x2-x+5)5x
Tìm x:
1/ 4.(18-5x)-12.(3x-7)=15.(2x-16)-6.(x+14) 2/5.(3x+5)-4(2x-3)=5x+3.(2x+12)+1 3/2.(5x-8)-3(4x-5)=4(3x-4)+11 4/5x-3.{4x-2.[4x-3(5x-2)]}=1821.Thuc hien phep tinh sau:
a,(3x^2-4x+5)(2x^2-4)-2x(3x^3-4x^2+8)
b,(1-3x+x^2)(2-4x)+2x(2x^2+5)
\(C=\left(\dfrac{2x-3}{4x^2-12x+5}+\dfrac{3}{1-2x}-\dfrac{2x-8}{2x^2-13x+20}\right):\dfrac{21+2x-8x^2}{4x^2-3+4x}+1\)
a) Rút gọn C
b) Tính C khi \(\left|x\right|=1\)
c) Tìm x thuộc Z để C thuộc Z
16 Tìm x, biết
a) 4(x+2)-7(2x-1)+9(3x-4)=30 ; b) 2(5x-8)-3(4x-5)=4(3x-4)+11
c) 5x(1-2x)-10(x+8)=0 ; d) (5x-3).4x-2x.(10x-3)=15
1/ Thực hiện phép nhân :
a) x2 ( 5x3 - x - \(\dfrac{1}{2}\))
b) ( 3xy - x2 + y ) \(\dfrac{2}{3}\)x2y
c) x2 ( 4x3 - 5xy + 2x ) ( -\(\dfrac{1}{2}\) xy )
2/ Tìm x, biết
a) 3x( 12x - 4 ) - 9x (4x - 3 ) = 30
b ) x( 5 - 2x ) + 2x ( x - 1 )= 15
tìm x
a)4(2x+1)2+(4x+2)(2-6x)+(3x-1)2=0
b) (6-x+4x2)(6+x-4x2)=36